The Biostatistics and Data Management Core (F) will be established in recognition of the critical need for statistical and data management expertise in the design, implementation, and analysis of clinical and basic research related to mental health in HIV/AIDS. The Core will provide Penn Mental Health AIDS Research Center (PMHARC) investigators with statistical collaboration for planning of exploratory investigations and proposal development, and data management and informatics expertise for research planning. The overall mission of Core F will be to encourage and facilitate high quality innovative, interdisciplinary and translational mental health in HIV/AIDS research in the PMHARC. The Core will promote the use of rigorous statistical and analytic methodologies and effective data management by working across the Core boundaries. The Core's specific aims will be to: Advise and collaborate with PMHARC investigators on study design, data management, and data analysis issues, including qualitative research and mixed model approaches; Evaluate feasibility of intervention studies and facilitate conduct of precursor pilot studies; Collaborate on the design, implementation, data management and analysis for up to four pilot studies per year, and develop and maintain a central database of longitudinal assessments on a core set of assessments of biomarkers related to HIV, mental illness, and co-morbidities across all pilot studies. Once a participant is enrolled into a pilot study, the core data collection will continue on that participant until the administrative end of the P-30; Provide statistical collaboration for research funding applications (e.g. ROI, R21, R34); Adapt or develop new statistical methods. Many projects on which Core statisticians provide collaboration can be completed with the use of standard statistical methods, but in some cases it is necessary to either adapt existing methods or develop new ones in order to achieve a satisfactory analysis. Mental health data carries with it substantial structural burdens that tax standard statistical methodology, issues of inference, and issues of appropriate design. These burdens include highly correlated data over time and correlation among various outcome measures. Thus Core F for this Center will be dealing with interesting but complex issues that might not present themselves in other environments (e.g. CFAR). It is expected that as individual ROIs are awarded, that Drs. Ellenberg, Morales, and Barg, the Biostatistics Analysis Center (BAC) and the Clinical Computing and Research Unit (CRCU) will be part of the research team as appropriate to size and complexity of study. In general, the Core's model will be to utilize personnel effort that is supported by the Core for pilot projects and preparation of funding proposals, with the subsequent funded grants providing direct support of the resulting collaborative research effort. Methodological work will also be financed by PMHARC core funding as well as from outside funding generated from external awarded grants.